The Impact of Cooperative Learning on EFL Achievers' and Underachievers' Motivation Based on Marginal Utility.

This study explores the change of EFL learners' motivation in learning English with the increase of CL time based on marginal utility. Thirty learners from an intact class in Grade 10 were selected through their performance on a piloted sample Preliminary English Test. Learners were assigned to achievers and underachievers groups. The questionnaire of motivation, based on the Attitude/Motivation Test Battery (AMTB), was given to both groups as a pretest. All participants underwent the same amount of teaching time and same material with the same teacher during seven-week CL, 35 sessions taking 45 minutes each. The same questionnaire was administered again at the end of one week, three-week, five-week and seven-week treatments respectively to both groups and their scores on the questionnaires were compared through an analysis of Paired Samples t-test and ANOVA. The findings showed that after one week CL, both the achievers' and underachievers' motivations were significantly improved compared with those in pretest; after three-week CL, the underachievers' intrinsic and extrinsic motivations and achievers' extrinsic motivation declined significantly compared with those of Week One, while the latter's intrinsic motivation has no significant change; after five-week CL, underachievers' motivation didn't change significantly compared with their motivation in the pretest, which means that the marginal utility took place in underachievers' motivation during three-week to five-week CL; after seven-week CL, the achievers' motivation increased significantly compared with their motivation in the pretest, indicating there was no marginal utility for achievers' motivation during seven-week CL. [ABSTRACT FROM AUTHOR]